Rotary well drilling apparatus



G. K.' CLAIRE ROTARY WELL DRILLING A PPARATUS June 17, 1941.

Filed March io, 1959 s 'Smeets-sheet 1v Gaf /f 62511K @www `une 17,1941. G, K CLAIRE V 2,245,960

ROTARY WELL DRILLNG APPARATUS Filed March 1o, 1959 s sheets-sheet 2' vJune 17, 1941.. v G. K. CLAIRE v2,245,960

' ROTARY WELL DRILLING APPAATUs Filed March 1o, 1939 :s sheets-sheet sVthreaded connections Patented June 17, 1941 Guy K. claire, mum-g mus,

Calif., assignor of one-third to Arthur L. Armentrout, one-third toElwin B. Hail, and one-third to Virgil P. Baker, f

i all of Los Angeles, Calif.

Application Maren 1o, 1939, serial No. 260,911l

18 Claims.

This invention relates to well drilling equipment and relates moreparticularly to a rotary table or rotary` for use in the rotary methodof Well drilling. A general object of this invention is to provide apractical effective and improved rotary table for rotating the ,wellstrings and for performing the other functions of typical rotary tablesand for making up and breaking down the drilling strings and othersectional well strings.

In the rotary method of well drilling a -power driven rotary table isprovided in the derrick to carry the bushings, slips and other devicesfor ing strings, the casing strings, etc. A weil string such as a rotarydrilling string is made up of a' plurality of stands of pipe connectedby threaded vcouplings and during the drilling operation a vpolygonal orfiuted kelly is connected in the upper portion of the string to operatethrough the rotary table. The kelly is engaged by a correspondingly toprovide a rotary transmitting drivebetween the table and the drillingstring. In making up and breaking down a rotary drilling string it isthe general practice to`support the string in the table by means oi'slips and to 'turn the uppermost stand of pipe while securing the lowerportion of the string against rotation. One set of tongs is usuallyengaged about a section of the tool joint at the table and another setof tongs is engaged about the other' section of the tool Joint. The lastnamed set of tongs is usually operated by aline handled by a cathead oithe draw works. The operation of the tongs and the` lines is a timeconsuming operation and is accompanied by considerable danger to theworkmen and equipment.' Furthermore, in making up the by tongs and ajerk line it is difilcult, if not impossible, to gauge the tor rsionapplied to the .connections and in many cases the threads of the pipeconnections are galled or strained 'endangering the entire weil stringand shortening 'the life o f the joints..

Rotary tables known as make and break rob' taries have been proposed tofacilitate the mak ing up and breaking down of the well strings.

' These make and break rotary vtables yusually ein# body inner and outerindependently rotatable table parts with means on the inner table parirto hold the pipe against turning and means on the outer table part tothe main inner table part,

is utilized to ro- (Cl. Z55-23) body practical or supporting andengaging the tool-carrying drillshaped bushing in the rotary tableengine' throughout the down the well strings. This e of the main powermeans of the rotary table to drive the outer table part is veryrespects. For example, it necessitates a special complicated means forconnecting and disengag-v ing the inner and outer parts of the table andrequires the continuous operation of the rotary erations. Furthermore,the make and break rotary tables that have been proposed do not emyeffective means for gauging the torque applied to well strings. brakemeans be utilized to ,hold one section of the table againstturning-during the making up of 'the'threaded joints. which brake ymeanswill release when a given torque Ais applied to the threaded connectionsy Such brake means are impractical, are not dependable. and do notassure the uniform appli tion of torque to the many joints of the drilng string.

Another object oi' this invention is to provide a rotary or a rotary"table operable to makeup down sectional well or thread together thejoints of a rotary well drilling string under a given uniform torque orrotational force to assure tion of the string sections and to preventgalling and straining of the threads.

Another object of this invention is to provide a rotary table operableto make up and break strings that embodies an automatic torque governeddrive or power means for rotating one part of the table, which power.means may be set or conditioned to make up the Joints underl a tionalforce.

, Another object of this invention is to provide given or selecteduniform rotaa' rotary table of the character mentioned emkbodying aring'or outer part rotatable relative to the inner table part to make upand break connections of the well strings and a separate drive and powermeans for .rotating the said outer part. The improved roturn the upperstand of pipe. In these sc-called make and break rotary- 'up Aandbreaking 55 tary table of the present invention embodies a drive ofsuitable or customary form for rotating the main inner table partanda'separate drive and power means for operating the outer table partto break and make the threaded joints of the wellfstrings.

Another obiect of this invention is to provide a rotary table of' thelcharacter mentioned in which the drivefor the outer table part may beutilized as an emergency drive or special drive for rotating the entiretable and thisy drive is torque controlled thereby adapting the rotaryta'- unsatisfactory in many making and breaking opg-A the threadedconnections of the It has been proposed that friction' the dependableconnec- `operative positions.

ble for use in special drilling operations, etc. where a torquecontrolled rotation of the well string is necessary. The drive for theouter table part is very important as it assures the continued operationof the drilling string in the event the regular drive fails and,therefore, makes it unnecessary to provide an expensive auxiliary drivemeans for the table.

Anpther object of this invention is to provide arotary table of thecharacter mentioned embodying novel, dependable and safe means forsupporting the pipe engaging tongs on the -base and outer table part foreasy manual movement between their operative positions about the pipeand retracted positions clear of the rotary table bushings. The tongsupporting means of the present invention are such that the tongs may beretracted to 4positions where they do not interfere with the drillingoperations at the rotary table and are such that the tongs may behandled with little or no danger to the workmen.

Another object of this invention is to provide a rotary table of thecharacter mentioned in which the .drive for the outer table part isfully controlled by simple, manual operations of a switch and brakelocated at a convenient station.

A further object of this invention is to provide a rotary table of thecharacter referred to including novel practical and effective means forsupporting the rotatable outer table part.

A still further object of this invention is to provide a rotary table ofthe character mentioned embodying means for visibly indicating therotational force being applied while making up the joints orconnections'.

The various objects and features of my invention will be fullyunderstood from the following detailed descriptionof a typical preferredform and application of the invention, throughout which descriptionreference is made to the accompanying drawings, in which:

Fig. 1 is a top or plan view of the rotary table of the presentinvention showing the tongs in the Fig. 2 is an enlarged fragmentaryvertical detailed sectional view taken substantially as indicated byline 2 2 on Fig. 1.

Fig; 3 is an enlarged fragmentary vertical detailed sectional view takenas indicated by line 3 3 on Fig. 2. Fig. 4 is an enlarged fragmentaryvertical detailed sectional view taken substantially as indicated byline 4 4 on Fig. 1. Fig. 5 is an enlarged fragmentary vertical detailedsectional view taken as indicated by line 5 3 on Fig. 1 with the motor,reduction gearing and other parts in side elevation. Fig. 6 is anenlarged vertical detailed sectional view taken substantially asindicated by line 6 6 on Fig. 5 with the motor in elevation. Fig. '1 isan enlarged fragmentary vertical detailed sectional view taken. asindicated by line 1 1 on Fig. 5.

may be said to comprise, generally, a base I0 to be mounted at the upperend of the well, an inner table part rotatably supported on the base Thebase l0 is provided to support the various operating elements of theapparatus and is support the inner part II.

Fig. 8 is an enlarged fragmentary vertical detailed sectional view takenas indicated by line 3 8 on Fig. 5 with the brake means in elevation.Fig. 9 is a'fragmentary side elevation of the brake means taken asindicated by line 9 9 on Fig. 8.

Fig. 10 is a wiring diagram of the circuits em- 'I'he improved rotarytable of this .invention adapted to be suitably mounted on the floor ofthe well derrick. The base I0 is provided with a generally rectangularlower part I6 to be secured to the supports of the table. The base I 0further includes an upstandingannular inner wall I1 surrounding ordefining the central vertical opening I9 of the base and an upstandingouter wall I9 spaced some distance from the wall I1. Webs 20 extendbetween and connect the lower portions of the spaced walls I1 and I9. Anupstanding intermediate wall 2| is spaced between the inner and outerwalls-I1 and I9 and is somewhat higher than the inner wall I1. Anannular flange 22 projects upwardly and outwardly from the outer wall I9to support the outer part I3 of the rotary table, as will be laterdescribed. A lateral or radial tubular extension 23 is provided at oneside of the base I0 to receive certain parts oi' the drive I2 for theinner table part I I. The extension 23 extends below the `ange 22 andits opening 24 continues inwardly through the outer base wall I9.

The inner table part is provided to' carry the bushings, slips, etc.employed in the various well drilling operations. The inner part of therotary table is an annular member or structure arranged in the base I0.In the preferred construction the inner table part includes a main upperportion 25 overlying the inner wall `II of the base I IJ and the channelor space between the walls I1 and 2|. A tubular depending flange 23 onthe upper portion 25 extends downwardly through the opening 8 inoverlapping relation to the inner wall I1 of the base I0. A suitableanti-friction bearing 21 is seated in the base I0 between the walls |1and 2| to rotatably The bearing 21 is seated against shoulders on theportion 25 and the wall 2| to take lateral thrusts as well as thevertical loads. An apron ring 28 is threaded to the lower portion of theflange 26 and has an annular upwardly facing channel 29. A bearing 30 isseated in the channel 29 to engage upwardly against a base web 20 forthe transmission of upwardV and lateral thrusts from the inner tablepart to the base I0. A suitable lubricant is provided in the channels ofthe base I0 carrying the bearings 21 and 30 and the adjacent portions ofthebase I0 and the inner part I| mesh or overlap to seal ofi.' thebearing carryingv channels.

The inner element or part of the rotary table is annular, being providedwith a central vertical opening 3| for receiving the bushing elements.The upper portion of the opening 3| is polygonal while the portion ofthe opening 3| extending through the flange 26 may be cylin'- drical. Anupwardly facing shoulder 32 occurs on the wall of the opening 3| betweenits cylindrical and polygonal portions. A master bushing 33 is arrangedin the opening 3| to seat on the shoulder 32. The upper portion of thebushing 33 is shaped to conform to the polygonal part of the opening 3|so that the bushing turns with support the shaft 2,245,960 The openingin the master the table part II. bushing 33 has a polygonal upper partfor receiving correspondingly shaped portions of kelly bushings, etc.The lower portion of the bushing opening 34 is tapered or conical toreceive slips 35. As illustrated in the drawings the slips 35 may beseated in the opening 34 to grip and support a well string S.

The drive means I2 for rotating the inner ta ble part II is provided todrive the table part II during the regular drilling operations, etc. The

drive means I2v includes a ring gear 35 secured to the inner table partI I. The ringl gear 36 may be integral with the main upper portion 25 ofthe table part I I or may be -a separately formed annular elementrigidly engaged about the portion 25 as illustrated in the drawings.`The upper surface of the ring gear with the topsurface of the portion25 and the master bushing 33. 'I'he lower side of the ring gear 36 hasan annular series of bevel gear teeth 31. An annular groove 38 in theunder side of the gear 36 receives a reduced upper edge portion of theintermediate base wall 2| to provide a seal.

The drive means I2 for the inner table part II further includes asubstantially horizontal shaft 39 extending inwardly through the opening2l in the table extension 23. Suitable bearings 40 39 for free rotation.'Ihe shaft 39 may be driven by any suitable power means. In the caseillustrated a sprocket 32 is keyed to the projecting outer portion ofthe shaft 39 and a chain 43 operated by the drilling engine (not shown)meshes with the sprocket B2 to rotate the shaft 39. A bevel pinion t4 isfixed or keyed to the inner end portion of the shaft 39 to mesh with theteeth 3l of the ring gear 38. Suitable means controlled by manual levers35 are lprovided in the extension 23 to lock the shaft 39 and theinnertable part II against rotation. The details of this shaft holding meansare not shown as they are well known to those skilled in the art. .Thebase I has a chamber 99 for carrying a bath of lubricant for the pinionM and the other operating parts. The upper portion of the outer basewall I9 is received in an annular groove 3l in the 'ring gear 36 to forma seal between the ring gear and the base. The inner the means I2 just`described is, of course, controlled by the driller in the usual manner.

The outer table part I3' surrounds the inner part II and serves to carryone unit oi the tong supporting means I5. In accordance with theinvention the outer table part I3 is in the nature of a ring surroundingthe ring gear 33 with some clearance. It is preferred to arrange thetablepart I3 so that its upper surface is in substantially the sameplane as the top surfaces of the inner part II and the ring gear 3B. Theouter table part I3 overlies the base flange 22 and is supported onbearing means 48. The bearing means 43 may comprise a series of ballslcooperating with an nul .-.r races'in the flange 22 and an annularsection 59 fixed to the outer table part I3. The section 49 may bepressed into the part I3 or otherwise fixed to it. The base flange 22 isdesigned to carry a lubricant bath for the bearing meansti. The upperedge portion of the flange 22 is received in a groove 59 -in the tablepart I3 to form a seal. Means is provided to prevent upward movement ofthe outer table part I3. A plurality of circumferentially spaced `posts5I is secured to the outer base Wall I9. The posts theouter table partI3.

36 is preferably flush 5I extend upwardly through openings in the flange22 and carry rotatable rollers 52 cooperating with a track part I3. Therollers 52 engaging in the track 53 prevent tilting and upward movementof the outer table part I3. A ring 54 is provided to close the annularspace between the ring gear 35 and The ring 54 may be secured to theposts 5I by screws 56B. In the preferred construction the ring 54 isdesigned to partially overlie the outer table part I3 to moreeffectively prevent the entrance of water, dirt, etc. to the flange 22.

The means )I4 for driving or rotating the outer table part I3 is animportant feature of the invention. The means I4 is operable to rotatethe outer table part I3 relative to the inner table part II in both the'righthand and the lefthand directions. In accordance with the inventionthe means I4 embodies an automatic torque control whereby the rotarytable is operable to make up the numerous joints of a wellstring undervauniform rotational force of a selected intensity.

The drive means Id includes a supporting bracket 55 projecting outwardlyor radially from 'I the outer wall I9 of the base I9 (see Fig. 5). Thebracket-55 is suitably fixed to the` base wall I9 and preferablyprojects outwardly in spaced diverging relation to the base extension23. The

power generating unit of the drive means I4 is mounted on ,the bracket55. erating unit of the means the nature of a reversible electric motor56 of a suitable rating, it being apparent that other^ employed 4as lli.The

equivalent prime movers may be the power generating unit of the meansymotor 56 is preferably of an explosion-proof table part I'I driven byvv the flange 22 by anti-friction In the preferred construction the motor56 is arranged so that its shaft 5l is radial relative to the commonaxis of rotation of the table parts II and I3. A suitable coupling 58connects type.

`the inner end of the motor shaft 51 with the shaft 59e of a gearedspeed reduction unit 60. The speed reduction unit 60 is suitably fixedto the bracket and the inner end of its shaft 59 projects inwardly underthe `table part I3. In accordance with the invention the motor 56 issupported to swing or turn on its axis under the influence of torque ordriving load. A cradle 5I is fixed to the under side of the motor 56 andhas inner and outer arms 62 and 63 projecting upwardly atv the oppositeends of the motor. A bearing post 53 projects upwardly at the outer endof the bracket 55 and has a bearing 65 rotatably supporting the outerend of the motor shaft 51. The arm bearing 63' adjacent the bearing 65assisting in 53 in the section 49 of the table.

The power genf I4 is preferably in 4 32 ofthe cradle 6I has a.

supporting the motor shaft 51. The inner cradle arm 33 has a similarbearing 6l`receiving the shaft 59a of the speed reduction unit 60. Itwill be seen that the cradle 6I assists in supporting the motor 56 andvis swingable or turnable. with the motor. The cradle 6I forms i ment ofthe lautomatic torque control, as will be subsequently described.

The drive means I4 further includes an annular series of bevel gearteeth 68 on the under side of the outer table part I3. A pinion 39 iskeyed portion' of the shait'59 and meshes withv the teeth 58. The flange22 of the base I0 is formed to receive the pinion 59 and to contain alubricant bath at the pinion. It will be seen that the motor 53 isoperable to rotate the outer table part I3 through the medium of amovable ele- The automatic torque control for the motor 56 includes ayielding means resisting turning of the motor resulting from a torqueload on the motor when the same is rotating the table part I3 in arighthand direction in making up the connectlons of the string S. Themeans for resisting swinging or turning of the motor 56 may include aweb 1I on the cradle and a helical spring 15 arranged against the web1I. A pin 16 is provided on the web 1| to hold the spring 15 againstdisplacement. The outer end of the spring 15 is arranged against a partto be later described and the spring serves to resist turning orswinging of the motor 56.

In referring to Fig. of the drawings it will be seen that the energizingcircuit of the motor 56 includes incoming power leads 18 extending froma suitable source of electrical energy. The leads 18 extend to areversing switch 19 for controlling the reversible motor 56. 'Ihe switch19 may be of any suitable form of remotely controlled reversing switch.For example, it may be a magnetic reversing switch of any well knowntype. Leads 89 extend from theswitch 19 to the motor 56 and thereversing switch 19 has a control circuit 8|. A manual switch 82 isconnected in the circuit 8| and is adapted to be operated to causeforward and reverse energizetion of the motor 56 and de-energization ofthe motor. The switch 82 may be a push button switch having a forwardbutton 83. a stop button 84 and a reversing button 85. The manual switch82 is preferably located for convenient operation by the operator ordriller. In practice I prefer to mount the switch 82 on a post 86projecting upwardly from the base portion I6 adjacent the base extension23. I

Visible indicating means is provided to indicate ythe rotational forceor torque being appliedv in making up the couplings and in performingother operations. This means includes a pressure gauge 10, that may bemounted on the post 86. The gauge 10 is calibrated in thousands offoot-pounds. A pipe or conductor 12 leads from the gauge to a. diaphragm13 supported by a bracket 14 on the bracket 55. The diaphragm 13 may belof the Sylphon type or of of the type shown. The outer end of the abovedescribed spring 15 engages a head 11 on the diaphragm 13. When thecradle 6I swings under the motor torque the spring 15 transmits force tothe diaphragm 13 and the gauge 10 indicates the torque force beingapplied to the coupling or work. The diaphragm head 11 is shaped toretainthe outer part of the spring 15. The operator observing the gauge10 may operate the switch 82 to make up the couplings at any selectedtorque force or rotational force.

The automa-tic torque control of the drive I4 further includes a stopswitch or limiting switch 81 connected in the common lead 88 of thecontrol circuit 8| between the switch 82 and the reversing switch: 19.The limiting switch 81 is mounted on the bracket 55 for adjustmenttoward and away from the web 1I and has a projecting pivoted or turnableoperating part 89. The switch 81 is positioned so that its operatingpart 89 is engaged and moved by the web 1I of the cradle 6I when themotor 56 swings under the influence of a load of a given intensity. Asillustra-ted in the drawings, the switch 81 has a pin |30 shiftable in aslot I3I in the bracket 55. A screw |32 is threaded through an openingin a lug |33 on the bracket 55 and cooperates with the switch 81 toadjust the same relative to the cradle web 1I. The screw |32 may bemanipulated to adjust the switch 81 to be operated by the web 1I whenany selected torque or force is applied to the work.

A nger |35 on the switch 81 cooperates with a scale |36 on the bracket55 to indicate the position of the switch in terms of the foot-pounds oftorque on the work required to cause operation of the switch. The switch81 may be spring urged to the closed position and actuation of the part89 by the web 1I effects opening of the switch 81. The stop button 84 ofthe switch 82 and the limiting switch 81 are both operable to open thecircuits to the coils or magnetic means of the reversing switch 19 toeffect deenergization of the motor 56. A lock nut |31 may be employed tolock the adjusting screw |32 in any selected position.

It may be desired to control the drive means I4 by the torque load toeffect de-energization of the motor 56 when the table part I3 is beingrotated in a lefthand direction to make up the connections in a lefthanddrilling string, or the like.4 It will be apparent that if this isdesired a switch similar to the switch 81 may be arranged to be actuatedby the web 1I when the motor 56 swings under a lefthand torque of agiven intensity to effect the deenergization of the motor 56. In thecase, illustrated, however,.a stop 90 is provided on the bracket 55 tolimit or prevent swinging of the motor 56 when the outer part I3 isbeing driven in a lefthand direction. The parts may be related so thatthe spring 15 described above normally holds the motor 56 in a positionwhere the cradle web 1I engages against the stop 90.

It is preferred to provide brake means to stop turning of the oute'rtable part I3 to facilitate the positioning of the tong supporting unitcarried by the outer table part. The brake means illustrated in thedrawings includes a drum 9| connected with the motor shaft 51. 'I'hedrum 9| may be connected with the coupling58. A brake band 92 carrying asuitable friction material surrounds the drum 9| and is supportedintermediate its ends by an adjustable anchor 93. The anchor 93 may becarried by a post 94 on the bracket 55. A lug 95 projects from an endoi' the brake band 92 and a spring 96 acts on the lug 95 to hold thebrake band 92 in the released condition. A shaft 91 is turnablysupported by the post 94 and a double-ended lever 98 is fixed to theshaft 91. A pivot 99 connects one end of the lever 98 with the other endof the brake band 92. A screw |00 is pivotally connected with the otherarm of the lever 98' and extends through the spring 96 to the lug 95 ofthe brake band 92. A nut IOI on the screw |00 engages lug 95 to actuatethe same upon turning of the lever 98.

A suitable brake operating linkage |02 is connected with a lever |03fixed on the shaft 91. The linkage |02 extends to a point adjacent thepost 86 carrying the manual switch 82 and is there provided with a pedal|03. The pedal |03 is conveniently operable by the operator controllingthe switch 86. Upon depression of the pedal I 03 the shaft 91 is turnedto tighten the brake band 92 on the brake drum 9| and thus stop rotationof the outer table part I3. By appropriate operation of the switch 82and the brake pedal |03, the outer table part I3 may be turned to anyselected rotative position.

/The tong supporting means I5 is provided to support a pair of tongs Tfor quick easy engagement with the string S above and below the joint orconnection to be threaded or unthreaded. One unit of the tong supportingmeans I5 is xed to the base I vand the other unit oi the means I iscarried by the outer table part |3. Thetong supporting unit of the meansI5 on the base I0 includes 'a vertical post |04 removably secured to thebase wall I9 and extending upwardly through an opening |05 in the ring54. The post |04 may be secured to the wall I9 by any suitable quickconnection means. For example, its lower end maybe removably held in asocket |30 on the wall I9 by a screw I3I. The unit of the tongsupporting 'means |5 on the outer table part I3 includes a similar post|06 having. a foot |01 bolted to the part I3.` The post |06 isconsiderably taller than the post wl but is otherwise of the samedesign. Stems |08 are shiftable and turnable in vertical openings IIIprovided in the posts IM and |06 and the stems are provided at theirupperv ends with heads |09. Springs I I0 are arranged under compressionbetween the lower ends of the stems |00 1 and the bottoms ofthe openingsI The springs ||0 counterbalance or partially counterbalance the stems|08 and the parts carried thereby. The stems |08 may be locked orsecured in the ad- .justed positions by clamp screws I I2. The heads mayremain stationary. At this time the heads l. |09' and thearms II4 may bein retracted posi- |09 are provided with horizontal openings ||3 toreceivetong carrying levers or arms IId.

The arms |I4 `are shiftable and turnable in the openings ||3 and projectinwardly toward the string S when in the active positions. The tongs Tare suitably secured to the inner ends of the arms Hd. Slots H5 areprovided in the heads |09 and the arms lIi have keys il@ adapted toengage in the slots H5 to hold the arms against turning. By shifting thearms Hd inwardly toward the center of the table their keys I6 may bedisengaged from the slots I i5 wherei uponthe arms may be reversed orturned 180 to invert the tongs T for right and lefthand operation. Stopheads H55 are provided on the arms il to limit this inward shifting of'the arms and to prevent disengagement of the arms from the heads |09.Springs Hte may be arranged under compression between the heads ii andshoulders ||1 to urge the arms ||i outwardly so that their keys IIBremain in cooperation with the slots |I5 during operation of the tongsT. The posts |00 and |06 are arranged to clear or pass one anotherduring rotation of kthe ta ble'part I3. The head |09 andthe arm Hd ofthe unit carried by the table part i3 pass :freely over the head |09 andarm IId oi the tong supporting unit on the base Ill. When the tongs Tare not in use the heads |09 may be turned to positions'where the armsHd and the tongs T do not interfere with operations. at the rotarytable.

Means is provided for connecting the inner and outer table parts I| andi3 for simultaneous rotation when it is desired to employ the torquecontrolleddrive means I@ in the voperation. oi well tools.- The meansfor connecting the inner and outer table parts and i3 may comprise barsH8 provided at their opposite ends with lugs IIB. The lugs H5 areadapted to engage in suitable openings IZ and |Z| in the tops of thetable parts |I and I3, respectively, whereby the bars ||3 serve toconnect the two table parte II and`fI3.

When the drilling string S is beingrotated to I. 5 operate a drillingtool, or the like. the inner table part -I| is rotated by the drivemeans I2 in the usual manner and the outer table part I3 tions where thetongs T are entirely clear of the inner table part II and the bushingscarried.

thereby. When the drilling string S is being assembled or made up theslips 35 are employed asl illustrated in Fig. 4 of the drawings tosupport the lower portion of the string S on the lnner table part I I.The adjusting screw |32 may be set so that the mechanism `will make Aupthe connections under any selected torque. The heads |09 andv the armsII4 are brought' to positions such as illustrated in Figs. 1 and 4 oithe drawings where the tongs T may engage about the upper and lowersections of the tool joint section or connection C being made up. Thetongs T are suppotedin such a manner that they may be easily vandquickly arranged in the operative positions about the parts of thecoupling C. The tongs T are supported by the arms |I4 and it isunnecessary to employ lines, cables, etc. to suspend and operate thetongs. When the tongs T have been properly engaged about the upper andlower sections of the connection C the forward button B3 of the manualswitch 8'2 may be depressed to Aenergize the motor 5E. The motor 56drives or rotates the outer table part 3 in a forward or righthanddirection and the tong T carried lby the outer table part is thusrotated relative to the lower tong T supported by the stationary baseI0. Prior to the connection of the tongs T with the coupling C thethreadsof the coupling may have been manually started or mated. Therotation of the outer table part i3 and its tongs T by the drive IIi iscontinued until the threads of the connection or coupling C tighten.This tightening down of the threads of the coupling C .of courseincreases the torque or load on the motor 56 and this increased loadresults in swinging of the motor 56.

When the threads of the coupling C have been tightened under a givenrotational force the web 'lI engages and operates the part 89 of theswitch 81 to open the switch and thus cause cle-energization of themotor 56. Thus the tightening of the coupling C ceases when the couplinghas been tightened a suitable or selected amount. The tongs T arethendisconnected from v,the string S and the string is lowered preparatoryto connecting another stand of the pipe with the upper end of thestring. The

switch 82 and the brake pedal |03 may be manipulated to bring the tongsupporting unit on the table part I 3 to the correct position where itstong T may engage the upper section of the .coupling C to be made up.The above operations may be repeated in making up the entire string S.

The screw |32 may be adjusted so that the torque controlled drive meansIt assures the making up of the several connections C under a givenrotational force. Accordingly, the string S maybe made up in such amanner that its This energizes the motor 56 to turn the outer table partI3 inl a counter-clockwise direction. The tongs 'I' carried by the baseI0 holds the lower part of the string S against rotation while the tongsT carried by the rotating table part I3 cause the upper stand or sectionof the string to rotate so that the threads of thel coupling C areunthreaded. When the coupling C has been broken or unthreaded the tongsT are disengaged from the string S and the upper detached section orstand of pipe is removed and laid down or stacked in the derrick; Thestring, S is raised to bring the next tool joint or coupling C above therotary table and the above operations are repeated until the entirestring is broken down.

In both making up and breaking down the joints of a well string, thestem |08 carried by the post |06 may be left free to shift vertically sothat the tongs T engaging the upper stand or section of pipe may shiftvertically while the threads are made up or unthreaded. In carrying outthe above described operations a single operator observes the gauge 'I0and may control the switch 02 and the brake |03 and two operators maymanipulate the tongs T. The operations may be carried out rapidly Withpractically no danger to the workmen or equipment.

In the event that the main drive I2 for the inner table part II fails oris out of commission the inner and outer table parts and I3 may beconnected by means of the bars IIB so that the drive I4 may be utilizedto operate the drilling tools. In this case the post |04 is detachedfrom the base |,0 and removed before the drive I4 is put into operation.In some cases it may be desired to employ the drive I4 to rotate thewell string for special operations where a torque controlled drive isdesired. The screw |32 may be adjusted so that the switch 87 0perates tode-energize the motor 56 when any ported on the base, an outer partaround the inner part rotatably supported on the base independently' ofthe inner part, means on the base and outer part to support tongs forengaging a well string, power means for rotating the outer part relativeto the inner part, and a control for de-energizing the power meansresponsive to the resistance to rotation of the outer part.

5. Apparatus for use with a rotary table having a drive comprising' arotatable part surrounding the table, an electric motor, a drive betweenthe motor and the said part, a cradle supporting the motor to swing inresponse to resistance to rotation of said part, and a controlresponsive to swinging of the motor for de-energizing the motor whensaid resistance reaches a given value.

6. A rotary table of. the character described comprising an inner part,a rotatable outer part around the inner part, means on the outer part tosupport tongs for engaging a well string, a

influencing said circuit to de-energize the motor when the motor moves agiven distance.

'7. A rotary table of the character described comprising an inner part,a rotatable outer part given or selected torque has lbuilt up in thedrilling string.

Having described only a typical preferred form and application oi myinvention, I do not wish to be limited or restricted to the specificdetails herein set forth, but wish to reserve to myself any variationsor modifications that may appear to those skilled in the art or fallwithin the scope oi the following claims.

Having described my invention, I claim:

l. A rotary table for well drilling comprising a rotatable inner tablepart, power means for rotating said inner part, a rotatable outer tablepart around said inner part, and a separate power means for rotatingsaid outer table part.

2. A rotary table for well drilling comprising a base, an inner tablepart supported on the base for rotation, drive means for rotating theinner table part, an outer table part around the inner table partrotatably supported on the base independently of the inner table part, aseparate drive for rotating said outer table part, and tong supportingmeans on the base and the outer table part.

3. A rotary table for well drilling comprising separately mountedrotatable inner and outer parts, drive means for rotating said innerpart, separate drive means for rotating the outer part independently ofthe inner part, and a control for the last named drive means responsiveto the resistance to rotation of the outer part.

4. A rotary table of the character described comprising a base, an innerpart rotatably suparound the inner part, means on the outer part tosupportv tongs for engaging a well string, a motor, a drive between themotor and said outer part, means supporting the motor to move inresponse to resistance to rotation of the outer part, a control circuitgoverning the motor, manual switch means for said circuit operable toinitiate and stop operation of the motor, and means iniluencing saidcircuit to de-energize the motor when the motor moves a given distance.

8. A rotary table of the character described comprising an inner part, arotatable outer part around the inner part, means on the outer part tosupport tongs for engaging a well string, a reversible motor, a drivebetween the motor and said outer part whereby the motor rotates saidouter part, means supporting the motor to move in response to resistanceto rotation of the outer part in at least one direction, manual controlmeans for initiating operation of the motor. and control means forstopping the motor in response to a given movement of the motor.

9. A rotary table of the character described comprising an inner part, arotatable outer part around the inner part, means on the outer part tosupport tongs for engaging a well string, a reversible motor, a drivebetween the motor and said outer part whereby the motor rotates saidouter part, means supporting the motor to move in response to resistanceto rotation of the outer part in at least one direction, manual controlmeans for initiating operation of the motor, control means for stoppingthe motor in response to a given movement of the motor, and means foradjusting the last named means to operate at a selected movement of themotor.

10. A rotary table o1' the character described comprising a base, aninner part rotatable on the base, an outer part around the inner partrotatably supported on the base independently of the inner part, meanson the base and outer part to support tongs for engaging a well string,power means for rotating the outer part independently of the inner part,manual control means for starting and stopping the power means. andbrake tatably supported on means for stopping -the said outer partin'any selected position. Y

11. A rotary table of the character described comprising an inner part,a rotatable outer part around the inner part, power means for drivingthe inner part, power means for rotating the outer part independently ofthe inner part, a torque control for de-energizing the last named powermeans when there is a given resistance to rotation of the said outernecting the said inner part with said outer part part, and means forcon-- to be driven by the said last named power means.

12. A rotary table of the character described comprising a base, arotatable inner part on the base, an outer part'around the inner partrotatably supported on the base independently of the inner part,releasable means for connecting the A table part supported on the basefor rotation,

drive means for rotating the inner table part, an outer table partaround `the inner table part rothe base independently of the 'innertable part, and a separate drive for rotating said outer table part.`

14. In a rotary table, the combination of a base, an inner table partrotatably supported cn the base, an outer table part around the innertable part rotatably supported on the base independently of the innerpart, and' anti-friction hold-down' means on the base holding the' outerpart against upward displacement. v `15. In a rotary table, thecombination of a base,

A table part, a second string-engaging tongs, and means extending aninner table part rotatably supported 'on the base, an outer table partaround the inner table part, a trough flange on the base, andanti-friction bearing means in the ange supporting the outer part on thebase for independent rotation, the iiangebeing adapted to containlubricant.

16. In a powerdriven rotary table, the combination of a base, an innertable part supported on the base for rotation, and an outer table partaround the inner table part rotatably supported on the baseindependently of the inner table part. 17-. In a rotary table forhandling a well string .having threaded couplings, a stationary base,

inner and outer table partsv separately mounted on the base forindependent rotatio a tong supporting unit on the outer part rotatabletherewith to support tongs where they may gripY the upper part of a wellstring coupling above said table parts, and a tong supporting unit fixedto the stationarybase 'inside of the .outer part andv ylin'ojectingupwardly therefrom to support tongs whereV they may grip the lower partof the well string coupling above said table parts.

18. In a rotary table, a'stationary base, inner and outer table partsseparately mounted on the base for independent rotation, means on theinner part -for supporting a well string, a unit on vthe outer tablepart for supporting upper stringengaging tongs, there being a spacebetween the .y

periphery of the inner table part and the outer unit for supportinglower through said space for securing said'second unit to the stationarybase. v

. GUY K. CLAIRE.

